Technologies to enable miniaturized DNA electrophoresis within fused silica capillaries (50-75 microns ID) have been under development over the last two decades. The large surface area to volume ratio in micron-sized capillaries leads to an effective loss of the resistive Joule heat, allowing the voltage limitations that are imposed in slab gel electrophoresis to be surpassed. Also implicated is the need to use higher electric fields to achieve higher DNA separation speeds in micro-channel systems. The development of DNA separation matrices for capillary electrophoresis systems remains an important endeavor, as the properties of the sieving polymers directly dictate the separation resolution and the migration behavior of DNA molecules, as well as the difficulty or ease of micro-channel loading of the matrix. Some of the commonly used matrices include agarose, polyacrylamide, hydroxyalkylcellulose [6], polyvinyl alcohol and its copolymers.
There is a tremendous emphasis on research to provide micro-fluidic integrated gene analysis systems with sample preparation and analysis processes on a single micro-fabricated substrate. Such systems demonstrate an overall reduction in size, reduced use of reagents, increased speed and accuracy of analysis, and increased portability for field use. The field applications of such devices, however, are limited by power requirements imposed by the highly resistive capillary columns. The typically applied DC voltages to gel filled micro-fabricated capillaries in order to execute electrophoresis run in several kilovolts (1-3 KV) which can be only achieved in a laboratory setup. For example, DNA separation generally requires electric field strength of 300-800 V/cm and an applied voltage of the order of 1-3 KV in electrophoresis applications. Therefore, there is a need for developing a novel class of matrices with increased conductivity, which enhances sample (i.e., a DNA charged on the matrix) mobility while retaining resolution.